System and method for using a pulse flow circulation for algae cultivation

Inventors

Hazlebeck, David A. • Zhang, Jiping • Wu, Xiaoxi

Assignees

General Atomics Corp

Abstract

A system and method for using a pulse flow to circulate algae in an algae cultivation apparatus are provided. In order to counteract the negative effects of biofouling on algae cultivation equipment, a pulse flow is created to periodically move through an algae cultivation apparatus. The pulse flow will dislodge algae cells adhering to various surfaces of the apparatus, and it will also create turbulence to stir up any algae cells which may have settled onto the bottom of the apparatus. To produce an increased fluid flow rate required to create an effective pulse flow, a sump, which is periodically filled with drawn algal culture from the apparatus, is located at an elevated position above the apparatus. When released, the algal culture travels through a transfer pipe and into the apparatus with gravity causing the algal culture to flow at a very high rate.

Core Innovation

The disclosed invention relates to an algae cultivation system that uses a pulse flow to circulate algae in an algae cultivation apparatus for growing an algal culture containing a biomass. Effluent of the algal culture is collected and used to create the pulse flow that circulates through the algae cultivation apparatus to promote turbulence and resuspension.

In one aspect, the pulse flow is created by an elevated flush tank positioned above the algae cultivation apparatus to receive effluent for release into a conduit. A circulation pump draws the effluent from the algae cultivation apparatus and transfers the effluent to the flush tank, and an activator governs release of the effluent from the flush tank into the conduit to create pulse flow through the algae cultivation apparatus.

Additional embodiments include photobioreactor and raceway pond configurations, and configurations with a cultivation pond constructed with a plurality of flush gates and flush segments between the flush gates. In the sequential flush-gate configuration, the pulse flow travels one segment at a time when the flush gates are opened in sequential order, and the activator initiates release from a sump to the cultivation pond.

Additional embodiments include gas exchange using a gas exchange tank in fluid communication with the algae cultivation apparatus, where the gas exchange tank enriches the effluent with CO2. A diverting valve controls flow of effluent from the algae cultivation apparatus to the gas exchange tank, and a return pipe returns CO2-enriched effluent back to the algae cultivation apparatus.

Claims Coverage

The document provides three independent claims covering pulse-flow algae circulation using an elevated flush tank with activator-governed release, an elevated flush-tank pulse system combined with a gas exchange tank using CO2 enrichment, and a cultivation pond with flush gates where culture is stored in a sump and released so pulse flow advances one flush segment at a time in sequential order.

Across the independent claims, the core coverage is pulse-flow circulation of an algal culture in an algae cultivation apparatus using effluent released from an elevated flush tank governed by an activator, optionally combined with a CO2-enriching gas exchange tank routed by a diverting valve and returned by a return pipe, and alternatively implemented in a cultivation pond where a sump stores culture and sequentially opened flush gates advance pulse flow one flush segment at a time.

Stated Advantages

Documented Applications